U.S. Pat. No. 4,197,297, issued Apr. 8, 1980, describes two processes for preparing N-[2-hydroxy-2-(p-methoxyphenyl)ethyl]-2-(2-chloro-3,4-dimethoxyphenyl)eth ylamine. The first involves reaction of 2-chloro-3,4-dimethoxyphenethylamine with p-methoxystyrene oxide and the second, condensation of 2-bromo-1-t-butoxy-1-(p-methoxyphenyl)ethane with 2-chloro-3,4-dimethoxyphenethylamine followed by removal of the t-butyl protective group. The intermediates and process of this invention are not only chemically unobvious from the previous art but give better yields with lower chemical and through-put costs.
The starting materials for the process of this invention are p-methoxyphenylglyoxal lower alkyl hemimercaptals which are described in U.S. Pat. No. 3,345,416 and H. Becker, et al., J. Am. Chem. Soc., 85 3410 (1963). These publications do not describe the facile reaction of the hemimercaptals with primary amines.